title: Self-assembly of palmitoyl lipopeptides used in skin care products.
abstract: The self-assembly of three cosmetically active peptide amphiphiles C16-GHK, C16-KT, and C16-KTTKS (C16 denotes a hexadecyl, palmitoyl chain) used in commercial skin care products is examined. A range of spectroscopic, microscopic, and X-ray scattering methods is used to probe the secondary structure, aggregate morphology, and the nanostructure. Peptide amphiphile (PA) C16-KTTKS forms flat tapes and extended fibrillar structures with high β-sheet content. In contrast, C16-KT and C16-GHK exhibit crystal-like aggregates with, in the case of the latter PA, lower β-sheet content. All three PA samples show spacings from bilayer structures in small-angle X-ray scattering profiles, and all three have similar critical aggregation concentrations, this being governed by the lipid chain length. However, only C16-KTTKS is stained by Congo red, a diagnostic dye used to detect amyloid formation, and this PA also shows a highly aligned cross-β X-ray diffraction pattern consistent with the high β-sheet content in the self-assembled aggregates. These findings may provide important insights relevant to the role of self-assembled aggregates on the reported collagen-stimulating properties of these PAs.
authors.affiliation: Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom.
authors.forename: Valeria
authors.initials: V
authors.lastname: Castelletto
authors.forename: Ian W
authors.initials: IW
authors.lastname: Hamley
authors.forename: Conor
authors.initials: C
authors.lastname: Whitehouse
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Matts
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Osborne
authors.forename: Ellen S
authors.initials: ES
authors.lastname: Baker
mesh_terms: D000595:Amino Acid Sequence; D003358:Cosmetics / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D055666:Lipopeptides / Q000737:chemistry*; D019308:Palmitic Acid / Q000737:chemistry*; D017592:Skin Care
chemical_list: D003358:Cosmetics; D055666:Lipopeptides; D019308:Palmitic Acid